mildew UK /ˈmɪl.djuː/US /ˈmɪl.d(j)u/verb 2noun 1forms 3 verb2 •To taint with mildew.Hee giues the Web and the Pin, squints the eye, and makes the Hare‐lippe; Mildewes the white Wheate, and hurts the poore Creature of earth. — 1603 •To become tainted with mildew.His bald purplish head now looked for all the world like a mildewed skull. — 1851 noun1 •A growth of minute powdery or webby fungi, whitish or of different colors, found on various diseased or decaying substances. formsmildewed · mildewing · mildews